SCORM Files - manual buttons not working on mobile devices with original state hidden.

Hi,

We have produced 500 short courses will Storyline 360. These are slightly older courses.

We have built manual navigation buttons and turned off the default Storyline ones, however on some devices these buttons are not showing.

We have built them on one slide which includes a video, the way the designer has done it is that the buttons do not show unless you hover over the video. Works great on a computer, on a mobile or tablet the buttons flicker on and off and you can't click them, meaning a user cannot advance to the next slide. The swipe function does however work but we have not mentioned this as an option for users, therefore a handful of our clients have come back confused. 

I know I can go in to each individual Storyline file and update the file, but with 500 of them I really don't want to do that.

Is there a way in the compressed SCORM file, to tell 1 particular slide that they can show the default Storyline previous and next buttons?  In the code or anything

Or can anyone else think of a way we can do this quickly?

Attached one of the files.